再学 GDI+[48]: 路径 - StartFigure、CloseFigure、CloseAllFigures

本例效果图:

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代码文件:

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unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;



type

  TForm1 = class(TForm)

    CheckBox1: TCheckBox;

    CheckBox2: TCheckBox;

    procedure FormCreate(Sender: TObject);

    procedure FormPaint(Sender: TObject);

    procedure CheckBox1Click(Sender: TObject);

    procedure CheckBox2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses GDIPOBJ, GDIPAPI;



procedure TForm1.FormCreate(Sender: TObject);

begin

  CheckBox1.Caption := 'CloseFigure';

  CheckBox2.Caption := 'CloseAllFigures';

end;



procedure TForm1.FormPaint(Sender: TObject);

var

  g: TGPGraphics;

  path: TGPGraphicsPath;

  p: TGPPen;

  b: TGPBrush;

  pts1,pts2,pts3: array[0..2] of TGPPoint;

  i: Integer;

begin

  pts1[0] := MakePoint(0, 30);

  pts1[1] := MakePoint(30, 0);

  pts1[2] := MakePoint(60, 30);



  for i := 0 to Length(pts1) do

  begin

    pts2[i].X := pts1[i].X + 80;

    pts2[i].Y := pts1[i].Y + 20;

    pts3[i].X := pts2[i].X + 80;

    pts3[i].Y := pts2[i].Y + 20;

  end;



  g := TGPGraphics.Create(Canvas.Handle);



  path := TGPGraphicsPath.Create;

  path.StartFigure;

  path.AddLines(PGPPoint(@pts1), Length(pts1));

  path.StartFigure;

  path.AddLines(PGPPoint(@pts2), Length(pts2));

  path.StartFigure;

  path.AddLines(PGPPoint(@pts3), Length(pts3));



  if CheckBox1.Checked then path.CloseFigure;

  if CheckBox2.Checked then path.CloseAllFigures;



  p := TGPPen.Create(aclRed, 2);

  b := TGPSolidBrush.Create(aclYellow);



  g.DrawPath(p, path);



  b.Free;

  p.Free;

  path.Free;

  g.Free;

end;



procedure TForm1.CheckBox1Click(Sender: TObject);

begin

  Repaint;

end;



procedure TForm1.CheckBox2Click(Sender: TObject);

begin

  Repaint;

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 139

  ClientWidth = 227

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  Position = poDesktopCenter

  OnCreate = FormCreate

  OnPaint = FormPaint

  PixelsPerInch = 96

  TextHeight = 13

  object CheckBox1: TCheckBox

    Left = 28

    Top = 105

    Width = 97

    Height = 17

    Caption = 'CheckBox1'

    TabOrder = 0

    OnClick = CheckBox1Click

  end

  object CheckBox2: TCheckBox

    Left = 120

    Top = 105

    Width = 97

    Height = 17

    Caption = 'CheckBox2'

    TabOrder = 1

    OnClick = CheckBox2Click

  end

end